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Sorbitol MacConkey Agar with BCIG (SMAC with BCIG)

[所属分类:培养基配方] [发布时间:2021-12-16] [发布人:网站管理员2] [阅读次数:] [返回]

Sorbitol MacConkey Agar with BCIG

(SMAC with BCIG)

山东拓普生物工程有限公司培养基配方 http://www.topbiol.com

Composition per liter:

Peptone..............................................................20.0g

Agar ..................................................................15.0g

Sorbitol..............................................................10.0g

NaCl....................................................................5.0g

Proteose peptone.................................................3.0g

Bile salts mixture ................................................1.5g

5-Bromo-4-chloro-3-indolyl-β-D-glucuronide

sodium salt....................................................0.1g

Neutral Red.......................................................0.03g

pH 7.1 ± 0.2 at 25°C

Source: This medium is available from Oxoid.

Preparation of Medium: Add components to

distilled/deionized water and bring volume to 1.0L.

Mix thoroughly. Gently heat while stirring and bring

to boiling. Autoclave for 15 min at 15 psi pressure–

121°C. Pour into sterile Petri dishes.

Use: A selective and differential medium for the de

tection of Escherichia coli O157 incorporating the

chromogen 5-bromo-4-chloro-3-indolyl-β-D-glucu

ronide (BCIG). The medium combines two different

screening mechanisms for the detection of E. coli

O157, the failure to ferment sorbitol and the absence

of β-glucuronidase activity. The non-sorbitol-fer

menting and β-glucuronidase-negative E. coli O157

will appear as straw colored colonies. Organisms

with β-glucuronidase activity will cleave the sub

strate, leading to a distinct blue-green coloration of

the colonies. The intestinal tract of ruminants is the

prime reservoir of E. coli O157 and other entero

haemorrhagic E. coli (EHEC) strains, therefore

meats derived from cattle, sheep, goat, and deer can

be expected to be contaminated. Foods implicated in

human illness related to E. coli O157 include meats,

dairy products, vegetables, salads, apple juice, and

water.